Out 26th April 2012, Ubuntu 12.04.
I been running Ubuntu 12.04 since the second Alpha, a few months now, having upgraded from 10.04 (released April 2010).
It’s a massive improvement from 10.04 so I highly recommend you upgrade if you running an older version.
If you running Windows or Mac… you need to seriously consider this. I been on Linux since 2007 and I have NEVER regretted that decision. No cost, no lock in. Just quality software.
So here is my little tutorial to get my friends up to speed and help with the upgrade.